| dc.description.abstract | Trivalent chromium (Cr3+) is an essential mineral required in quantum with reported health
benefits. Chromium deficiency has been linked to symptoms associated with onset of adult
diabetes and cardiovascular diseases. Its essentiality and presumed functions in the
gastrointestinal tract remain poorly understood. Therefore, the effects of Cr3+ on some
gastrointestinal functions in normal and injured gut of rats and mice were investigated.
Sixty male Wistar rats (90.1±3.5 g) were grouped into three (n=20): Control (distilled water), 10
ppm (Cr3+) and 100 ppm (Cr3+) exposed for twelve weeks. After Cr3+ exposure, rats (n=5 per
group) were sacrificed (day 0). Thereafter, experimental gastric ulcer and colitis were induced
using acetic acid (50%, 0.2 mL) and (6%, 1 mL), respectively and rats were sacrificed on days 3,
7 and 14. Blood was processed to serum by centrifugation, while processed tissues were
homogenized. Blood Cr3+, haematological parameters, gastric acid secretion, ulcer and colitis
scores and histology were determined using standard methods. Myeloperoxidase (MPO),
Superoxide Dismutase (SOD) and malondialdehyde (MDA) were determined using
spectrophotometry. Rats were used for the in vivo intestinal motility study using standard
methods. In another experiment, 60 slc:ddY mice (26.2±1.1 g) were grouped and treated
according to the previous experiment. Stomach and colon tissues were quantified for selected
cytokines mRNA using real-time PCR. In vitro intestinal motility and glucose uptake were
determined by Magnus and spectrophotometry methods, respectively. Data were analysed using
descriptive statistics and ANOVA at α0.05.
Blood Cr3+ in rats was significantly increased in 10 ppm (0.17±0.01 Vs 0.11±0.02 ppm) and 100
ppm (0.19±0.02 Vs 0.11±0.02 ppm). Platelet counts, stomach mucosa width and colon crypt
height were significantly increased in normal tissues in 10 ppm (48.92%, 53.43%, 23.41%) and
100 ppm (39.70%, 58.00%, 25.42%) Cr3+ exposed rats compared with control, respectively.
Basal gastric acid secretion was significantly reduced in both 10 ppm and 100 ppm compared
with control on day 3. Gross ulcer area and histology scores were reduced in both 10 ppm and
100 ppm on day 3 (44.26±1.13 mm2, 27.42±2.49 μm), (37.70±2.04 mm2, 14.54±1.55 μm) and
day 7 (3.12±0.22 mm2, 2.16±0.12 μm), (2.94±0.12 mm2, 2.02±0.19 μm) compared with control
(50.83±1.90 mm2, 45.33±3.23 μm), (4.01±0.27 mm2, 3.76±0.16 μm), respectively. Colon gross
and histology scores after injury decreased in both 10 ppm and 100 ppm on day 3 (42.04%,
46.06%), (47.35%, 52.08%) and day 7 (58.90%, 37.10%), (100.00%, 59.42%) compared with
control, respectively. The MPO and MDA in 10 ppm and 100 ppm groups reduced significantly
compared with control, while SOD activities increased significantly in Cr3+ groups in both
tissues. In mice, total RNA in stomach increased in normal and day 3 post injury of stomach and,
colon of 10 ppm, 100 ppm compared with control, respectively. Chromium increased
expressions of IL-10, while suppressing TNF-α, IFN-λ mRNA during healing in both tissues.
Glucose uptake and motility were significantly reduced in all studies.
Chromium promoted healing of gastrointestinal injury by suppressing oxidative stress and
inflammation via down regulation of tumor necrotic factor-alpha and up-regulation of
interleukin-10 mRNA gene expressions. | en_US |
